Laozi (, Chinese: 老子), also romanized as Lao Tzu and various other ways, was a semi-legendary ancient Chinese philosopher, author of the Tao Te Ching, the foundational text of Taoism along with the Zhuangzi. Laozi is a Chinese honorific, typically translated as "the Old Master". Modern scholarship generally regards his biographical details as invented, and his opus a collaboration. Traditional accounts say he was born as Li Er in the state of Chu in the 6th century BC during China's Spring and Autumn period, served as the royal archivist for the Zhou court at Wangcheng (in modern Luoyang), met and impressed Confucius on one occasion, and composed the Tao Te Ching in a single session before retiring into the western wilderness. A central figure in Chinese culture, Laozi is generally considered the founder of Taoism. He was claimed and revered as the ancestor of the 7th–10th century Tang dynasty and is similarly honored in modern China as the progenitor of the popular surname Li. In some sects of Taoism and Chinese folk religion, it is held that he then became an immortal hermit, or that the Tao Te Ching was the avatar – embodied as a book – of the god Laojun, one of the Three Pure Ones of the celestial bureaucracy. The Tao Te Ching had a profound influence on Chinese religious movements and on subsequent Chinese philosophers, who annotated, commended, and criticized his work extensively. In the 20th century, textual criticism by modern historians led to theories questioning Laozi's timing or even existence, positing that the received text of the Tao Te Ching was not composed until the 4th century BC Warring States period, and was the product of multiple authors.